Point z is translated right 1, down 8
which is the point the coordinate pair for the translated point z?

Original coordinate:
Z (0, 4)

Translation being used: (x, y) > (x+1, y-8)
Since your going one unit to the right, then you would be adding since your x is increasing. Since your going eight units down, then you would be subtracting from your y since it's decreasing. 

X coordinate translation:
(1, __)

Y coordinate translation:
(__, -4)

New coordinate:
(1, -4)

HOPE THIS HELPS! ^_^